Method for controlling the pitch angle of wind turbine blades

Abstract

A method for controlling the pitch angle of the blades including the following steps of: measuring an energy storage of the blades pitch actuation system at predefined values of a first blade pitch angle interval; comparing the measured values of the energy storage of the blades pitch actuation system with a predefined minimum value of the energy storage; if the measured values of the energy storage are all greater or equal than the predefined minimum value of the energy storage then enabling normal operation; if at least one of the measured values of the energy storage are lower than the predefined minimum value then: calculating a third pitch angle calculating a third blade pitch angle interval extending between a fourth pitch angle and the second pitch angle; and limiting the blades pitch actuation system to operate only in the third pitch angle interval.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to PCT Application No. PCT / EP2019 / 051454, having a filing date of Jan. 22, 2019, which is based off of European Patent Application No. 18154439.6, having a filing date of Jan. 31, 2018, the entire contents both of which are hereby incorporated by reference.FIELD OF TECHNOLOGY[0002]The following relates to a method for controlling the pitch angle of the blades of a wind turbine.BACKGROUND[0003]Normally, any wind turbine is provided with a pitch actuation system (either electric or hydraulic) for regulating the pitch angle of each blade, i.e. the angular position of each blade about the respective blade longitudinal axis. The pitch angle defines the angle of attack of the blades in relationship to the direction of the wind to control the production of power of the wind turbine.[0004]The pitch actuation system of a wind turbine is provided with energy stored for emergency shutdown of the turbine. On a regular...

AI Technical Summary

Benefits of technology

This approach allows the turbine to remain operational at reduced output, increasing availability and Annual Electricity Produced (AEP) by identifying a safe pitch angle interval where the turbine can operate safely, reducing the need for immediate maintenance and minimizing production losses.

Problems solved by technology

The approach is that the turbine is not safe to operate if, under any circumstances, the pitch actuation system cannot overcome all and any wind load starting from any pitch position.

However, during the service time needed for the re-establishment of the capacity of the pitch actuation system, the wind turbines is not operative, costing significant number of production hours.

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